1. Field of Invention
The invention relates to an address monitoring device and an address monitoring method, and, in particular, to a memory address monitoring device capable of monitoring the condition when a processing circuit accesses a memory, and an address monitoring method.
2. Related Art
With the progress of the semiconductor manufacturing process, various types of chips, such as a processor, a controller or a memory, have higher and higher working frequencies, and many circuits may be integrated in one chip such that the working ability of the chip can be enhanced. In a digital data system, the data processing efficiency can be enhanced according to the working clock of the chip, such as that of the processor or the controller, and also can be enhanced through a multi-task mode.
A digital video/audio player, for example, receives digital video/audio data from an optical drive, a network or a wired/wireless television. Next, the digital video/audio player performs the process of variable length decode (VLD), inverse scan, inverse discrete cosine transform (IDCT) or inverse discrete wavelet transform (IDWT), inverse quantization, motion compensation or television encode on the digital video/audio data, such that the complete video/audio can be correctly played. These processes can be implemented by a program code or a circuit, or performed in a multi-task mode simultaneously. When these processes are being executed, the digital video/audio player allocates an independent memory sector to each process such that data can be saved and used in each process. In addition, these processes can be implemented by firmware or hardware in the same processing circuit, or in different independent processing circuits.
As shown in FIG. 1, in a memory 11 of a conventional digital video/audio player 1, sectors 111 and 112 are allocated to processes 121 and 122 for usage, respectively, and data for the processes 121 and 122 are saved in the sectors 111 and 112. When the process 121 is being executed, the video/audio data is stored in the sector 111. At this time, if the process 121 wrongly writes the data in the sector 112, the process 122 provides the wrong data, and the digital video/audio player may finally play the wrong frame.
In order to avoid the above-mentioned condition, the developer has to develop the processes 121 and 122, to debug strictly in the testing phase, and to monitor the reading state of the memory, such that the wrong procedure can be found, the occurrence of the above-mentioned condition can be decreased, and the digital video/audio player can correctly play the video.